The invention relates to a valve device for a medium and to an airbag for a motor vehicle.
From standard motor vehicle production, protective devices are known that include so-called airbags, which containers for air of which at least the volume can be varied. If the motor vehicle hits a barrier, these are inflated within a very short time by means of a gas discharge.
The purpose of this is the protection of occupants of the motor vehicle against hitting components in an occupant cell of the motor vehicle. Because such an impact leaves very little time for inflation this inflation and the corresponding protective function have to be available within a very short time.
Exemplary embodiments of the present invention are directed to a valve device for a medium and an airbag that allows the medium to very fast and efficiently flow through the valve device and in the airbag.
The valve device according to the invention for a medium, in particular for a gaseous medium of an airbag, comprises a textile layer, in particular a woven fabric, which permeable with respect to the medium at least in certain regions, and at least one film which covers the textile layer in at least one region. This film creates at least one passage region of the valve device that is at least substantially closed in a closed position of the valve device and at least substantially prevents a passage of the medium through the valve device. In an at least temporary passage position of the valve device, the passage region is open at least in certain regions and allows a passage of the medium through the valve device.
Such a valve function of the valve device and in particular of the film allows a particularly good, fast and efficient passage of a large quantity or volume of medium through the valve device in a very short time, which offers great advantages if the valve device is used in an airbag, because such an airbag has to be filled within a very short time with a specific quantity of the medium, in particular air, in order to ensure a high and fast volume increase to protect occupants of a motor vehicle with such an airbag. The valve device according to the invention can, however, be used in various other applications in which a valve function is desirable.
In addition to its excellent functionality, the valve device according to the invention offers the advantage that it has a very low weight and only a small pack volume. This is due to the fact that the film and the textile layer are extremely thin and light-weight. The costs of the valve device according to the invention are extremely low as well, because both the film and the textile layer can be produced fast and cost-effectively in bulk.
It should be noted here that the film is at least substantially impermeable to the medium, for example air. The medium can therefore only flow through the valve device by way of the passage region while being unable to flow through the valve device in other regions, being essentially prevented by the film.
The valve device according to the invention can be used in protective devices comprising at least one airbag, the airbag being, for example, a large continuous unit which, in an inflated state, occupies a defined, preferably large, volume in the interior of the motor vehicle. In such an application the valve device is used to let a desired quantity or volume of air flow into the airbag in the passage position when the airbag is inflated, i.e., its volume is increased. If the airbag is inflated and hit by an occupant, the valve device at least substantially retains the air in the airbag in its closed position and prevents a discharge and/or an excessively fast discharge of the medium from the airbag in order to provide a defined and desired support by the airbag.
The valve device according to the invention can also be used in a so-called truss airbag, which for example has a truss structure which is formed of a plurality of tubular elements of variable volume and which, if a force is applied to the motor vehicle in an accident, is inflated and occupies a defined volume in the interior of the motor vehicle. Compared to the continuous airbag described above, such a truss airbag offers the advantage that, while the truss structure is able to occupy as large a volume in the interior as the airbag described above and therefore provides equally good support, the overall volume to be filled with medium, i.e., to be inflated, is smaller. In other words, the sum of individual volumes of the tubular elements can be less than a volume of the large continuous airbag, but, owing to the truss structure provided by the tubes, the airbag can occupy at least as large a volume in the interior as the continuous airbag and can therefore offer the same support and protective function for the occupants.
To improve its support function, the truss structure is, for example, provided with a cover, in particular with a woven fabric, so that the truss structure and the cover form an interior of the truss airbag that is filled with a medium, for example air, and in particular ambient air, in order to improve the support function of the truss airbag even further. The cover of the truss airbag is advantageously at least partially represented by the valve device according to the invention, which therefore allows the interior bounded by the truss structure and the cover to be filled with a large quantity of medium, in particular ambient air, within a short time. The interior is therefore to be considered analogous to the large continuous airbag described above and offers at least as good a support and protective function, but the truss airbag can make these functions available within a shorter time. This means that it can occupy a larger volume than the continuous airbag within the same time, therefore offering an improved support and protective function. But even in the large continuous airbag which is at least partially represented by the valve device, the valve device according to the invention offers the advantage that the large continuous airbag can be filled with a particularly great quantity or volume of the medium within a very short time.
In view of this, it is obvious that the valve device according to the invention can be integrated into the continuous and/or truss airbag in a particularly simple and cost-effective way and in addition forms a homogenous surface that prevents or at least reduces the risk of injury to an occupant, in particular in the head region, if the occupant hits the airbag.
In one embodiment of the invention, the passage region described above is designed as a through-opening of the film, which is, for example, represented by a perforation. Such a perforation can be, for example, provided during the production of the film by means of a porcupine which forms a plurality of such perforations in the film, resulting in a particularly cost-effective production process and a highly efficient and excellent valve function of the valve device according to the invention.
In an advantageous variant of the invention, at least one flap element corresponding to the at least one through-opening of the film is provided, which flap element opens the at least one through-opening in the at least temporary passage position of the valve device at least in certain regions and closes it in the closed position of the valve device at least in certain regions. The flap element is advantageously designed as a single piece with the film, resulting in a low number of components and therefore in a low weight and low costs of the valve device.
As an alternative or in addition, it can be provided in a further embodiment of the invention that the passage region is represented by at least one film region that can be lifted off the textile layer in the passage position. To improve its tightness in the closed position, this passage region is in one embodiment closed by at least two film regions that overlap in the closed position of the valve device. This means that the film has at least two overlapping regions, which in turn cover a region of the textile layer. The overlapping film regions open up the region of the textile layer in the passage position of the valve device at least in certain regions while at least substantially closing it in the closed position of the valve device. This enables the medium to flow through the valve device particularly efficiently and well, while efficiently and effectively preventing a flow of medium in the opposite direction.
The invention further includes an airbag for a motor vehicle provided with at least one valve device according to the invention. Advantageous variants of the valve device according to the invention should be considered as advantageous variants of the airbag according to the invention and vice versa. As explained in the context of the valve device according to the invention, the airbag according to the invention can be filled with a very large quantity or volume of medium within a particularly short time, allowing its volume to be increased within a particularly short time to provide an excellent support and protective function for occupants of the motor vehicle. This applies both to large continuous airbags and to truss airbags as well as to any other airbag designs.
Further advantages, features and details of the invention can be derived from the following description of several preferred embodiments and from the drawings. The features and combinations of features referred to above and the features and combinations of features mentioned in the description of the figures and/or shown in the figures only can be used not only in the stated combination, but also on other combinations or individually, without leaving the scope of the invention.